IMHE OpenIR
溪洛渡库区生态环境变化遥感监测与评价研究
Alternative TitleStudy on Remote Sensing Monitoring and Evaluation of Eco-environmental Change in Xiluodu Reservoir Area
张茜彧
Subtype博士
Thesis Advisor范建容
2018
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline自然地理学
Keyword水电工程 土壤侵蚀 悬浮泥沙含量 遥感监测 生态环境评价
Abstract水电是一种重要的可再生绿色能源,但水电工程建设规模庞大、施工时间较长,在施工和运行过程中对生态环境的影响复杂,包括动植物多样性、局地气候、水文情势、水土流失、水温水质等方面。因此,水电工程对局地生态环境的扰动过程、扰动程度、评价方法和评价指标信息提取技术等科学技术问题亟待进一步探索,以期快速、科学评价水电工程的建设和运行对生态环境,特别是流域“水土安全”问题造成的影响。本论文选择位于金沙江干流的溪洛渡水电工程为研究对象,开展针对水电工程的生态环境变化监测与评价研究,具有重要理论意义和应用价值。溪洛渡库区在水电工程修建前土壤侵蚀较为严重,生态环境恶劣,梯级水电工程修建后对于当地落后的经济发展有良好的推动作用,但会造成流域生境、植被和水文泥沙的变化。因此本研究利用多期多源遥感影像、野外调查实测等数据,基于决策树分类、像元二分模型及通用水土流失方程获取研究区土地覆被类型、植被盖度和土壤侵蚀变化状况;实测水样悬浮泥沙含量,构建山区河流表层悬浮泥沙含量遥感反演模型;针对溪洛渡水电工程引发的生态环境问题,基于压力-状态-响应框架选取化肥施用强度、人口密度、公路密度、工程施工强度、坡度、年降水量距平、土壤侵蚀强度、植被覆盖度、河流悬浮泥沙含量、生境质量指数、城镇化率、人均GDP、自然保护区指数和中学在校人数比共计14个评价因子,实现基于遥感技术的适用于水电工程的的生态环境评价。研究取得了以下主要成果:(1)查明了工程对库区生态环境的扰动、变化状况。施工前后对比发现:耕地面积不断减少,森林面积不断增加,其他主要植被类型如旱地、灌丛和草地面积变化不明显;植被盖度有所升高,土壤侵蚀面积减少;施工前土壤侵蚀集中在金沙江干流及其支流美姑河、西苏角河河谷区域,施工期和施工后集中在工程施工及新建公路区域。虽然工程建设占用土地,水位上涨淹没大量耕地、园地和灌丛,但由于金沙江下游从1998年开始的“退耕换草”、“退耕还林”、改土造田、长江防护林工程等水土保持治理政策,溪洛渡水电工程并未对流域内陆生生境造成严重的破坏。(2)揭示了山区河流悬浮泥沙含量时空分布特征。溪洛渡蓄水后库区干流河段悬浮泥沙含量骤降,汛期从原来的1200至2500mg/L降到250至500mg/L,非汛期从原来的100至500mg/L降到50至150mg/L。支流悬浮泥沙含量蓄水后依然较高,汛期普遍在800至5500mg/L,非汛期150至1300mg/L,空间分布差异大。金沙江干流白鹤滩至向家坝段本为天然河流,流速快,水流挟沙能力大,悬移质含量高。水库蓄水后,河段水流速度变缓,挟沙能力下降,悬浮泥沙含量有所降低。但在西溪河、美姑河、西苏角河等支流由于其流域土壤侵蚀强度并未显著降低,其悬浮泥沙含量依然较高。(3)实现了溪洛渡库区布拖县、金阳县和雷波县生态环境评价。三县在1998年压力值相当,经济发展程度都比较低,雷波县自2007年溪洛渡水电站施工以来,压力值剧增。雷波县、金阳县和布拖县毗邻,分布在金沙江干流左岸离溪洛渡水电工程由近到远的位置。溪洛渡工程对于雷波县的影响是最大的,金阳县次之,布拖县最小,表现在2007年施工期的压力指数上,雷波县(7.49)和金阳县(6.87)均显著高于布拖县(3.96)。在溪洛渡工程的运行期,三县的压力较施工期均有所降低,但雷波县和金阳县略高于1998年溪洛渡工程未修建时的压力。布拖县在2016年的压力小于1998年。三个县的状态指标从1998到2016年都逐渐降低,说明三县的自然环境都越来越好。横向对比,布拖县和金阳县自然环境状态较雷波县稍差,但响应值较雷波县更高,主要是由于当地设立了大面积的自然保护区。本研究的创新点在于采用Sentinel-2号卫星、Landsat系列卫星影像和实测资料构建了山区河流悬浮泥沙含量遥感反演模型,解决了单一传感器影像无法满足山区河流悬浮泥沙含量遥感反演需求的问题,揭示了山区河流表层悬浮泥沙含量时空分布特征,并为后续的生态环境评价和监测分析提供遥感技术支撑。在获得以上成果的同时,本研究主要存在以下不足之处:(1)未充分考虑消落带对土壤侵蚀分布造成的影响。(2)基于实测数据的悬浮泥沙含量遥感反演模型只能获取水体表层的悬浮泥沙含量。(3)因条件限制,野外调查中没有实测研究区水体光谱,对于悬浮泥沙含量遥感反演的物理机制认识不足。
Other AbstractHydropower is an important renewable green energy. However, the scale of hydropower projects is large and the construction time is long. The impact on the ecological environment during construction and operation is complicated, including the diversity of plants and animals, local climate, hydrological conditions, soil erosion, water temperature and water quality, etc. In order to quickly and scientifically evaluate the impact of the construction and operation of hydropower projects on the ecological environment, especially the “water and soil safety” problem in the river basin, the scientific and technical issues such as the disturbing process of the hydropower projects on the local ecological environment, the degree of disturbance, the evaluation method, and the information extraction technology of the evaluation index need to be further explored. This paper selected the Xiluodu hydropower project located at the mainstream of the Jinsha River as the research object, and carried out research on the monitoring and evaluation of ecological environment changes for hydropower project, which has important theoretical and application values.Xiluodu reservoir area had serious soil erosion before the construction of the hydropower project, and the local ecological environment was poor. The construction of cascade hydropower projects promoted the backward economic development of the area, but caused changes in the habitat, vegetation and hydrological sediments of the river basin. Therefore, this study used multi-period and multi-source remote sensing images and field survey data to obtain land cover type, fractional vegetation cover and soil erosion status in the study area, based on the decision tree classification, the dimidiate pixel model and the revised universal soil loss equation. Then, the suspended sediment concentration of the water samples was measured, and a remote sensing inversion model was constructed for the suspended sediment concentration in the surface of the mountainous rivers. Finally, aiming at the ecological and environmental issues caused by Xiluodu hydropower project, the evaluation of ecological environment suitable for hydropower projects based on remote sensing technology was implemented. Based on the pressure-state-response framework, 14 evaluation factors were selected: chemical fertilizer application intensity, population density, road density, project construction intensity, slope gradient, annual precipitation anomaly, soil erosion intensity, fractional vegetation cover, river suspended sediment concentration, habitat quality index, urbanization rate, per capita GDP, nature reserve Index and school attendance ratio.The research achieved the following major results:(1) The disturbances and changes in the ecological environment of the reservoir area were identified. The changes before and after the construction found that: As the area of arable land continues to decrease, the area of forests continues to increase, and other major vegetation types such as dry land, shrubs and grassland do not change significantly. Fractional vegetation cover increased and soil erosion area reduced. Before the construction, soil erosion was concentrated in the mainstream of the Jinsha River and its tributaries, such as the Meigu River and the Xisujiao River Valley. Soil erosion during the construction period and after construction is concentrated in the construction area of the project and the construction area of new roads. Although a lot of arable land, parkland and shrubs were occupied by the project construction or inundated due to the increased water level. However, Xiluodu hydropower project did not cause serious damage to the terrestrial habitat in the river basin due to the water and soil conservation management policies of the lower reaches of the Jinsha River since 1998, such as “returning farmland for grasslands”, “returning farmland to forests”, reforming the land for production, and the Yangtze River protection forest project.(2) The temporal and spatial distribution of suspended sediment concentration in mountainous rivers was revealed. After the impoundment of Xiluodu project, the suspended sediment concentration in the mainstream of the reservoir area plummeted, from the original 1200 - 2500mg/L to 250 - 500mg/L in the flood season, and from the original 100 - 500mg/L to 50 - 150mg/L in the non-flood season. The suspended sediment concentration of the tributaries was still high after impoundment, generally ranging from 800 to 5500 mg/L in the flood season and 150 to 1300 mg/L in the non-flood season, with a large difference in spatial distribution. Before the impoundment of Xiluodu project, the mainstream of the Jinsha River from Baihetan to Xiangjiba was natural river with fast flow, large sediment carrying capacity and high suspended sediment concentration. After the impoundment of the reservoir, the water velocity of the river section was slowed down, the sediment carrying capacity was decreased, and the suspended sediment concentration was reduced. However, the suspended sediment concentration of the tributaries, such as Xixi River, Meigu River and Xishujiao River, remained high, because soil erosion intensity of their river basin did not significantly reduce.(3) The ecological environmental assessment of Butuo County, Jinyang County and Leibo County in Xiluodu Reservoir Area was implemented. In 1998, the three counties had similar pressure values and relatively low levels of economic development. Leibo County has experienced a dramatic increase in pressure values since the construction of the Xiluodu Hydropower Station in 2007. Leibo County, Jinyang County, and Butuo County are located on the left bank of the mainstream of the Jinsha River, adjacent to each other from the near to far from Xiluodu Hydropower Project. Xiluodu Project has the largest impact on Leibo County, followed by Jinyang County, and the lowest in Butuo County. For the pressure index during the construction period in 2007, Leibo County (7.49) and Jinyang County (6.87) were significantly higher than Butuo County (3.96). During the operation period of the Xiluodu project, the pressure in the three counties was lower than that during the construction period. However, the pressure values in Leibo County and Jinyang County are slightly higher than those in 1998 when Xiluodu Project was not constructed. Butuo County's pressure in 2016 was less than in 1998. The state indicators of the three counties have gradually decreased from 1998 to 2016, indicating that the natural environment of the three counties is getting better and better. In horizontal comparison, the natural environmental conditions in Butuo County and Jinyang County are slightly worse than that in Leibo County, but their response value is higher than that in Leibo County, mainly due to the establishment of large-area nature reserves in the local area.The innovation of this research is the use of Sentinel-2 satellite, Landsat series satellites images and measured data to construct a remote sensing inversion model for suspended sediment concentration in mountainous rivers. The research solved the problem that the single sensor satellite image cannot meet the remote sensing inversion demand of suspended sediment concentration in mountainous rivers and revealed the temporal and spatial distribution of surface suspended sediment concentration in mountainous rivers. The research results can provide remote sensing technology support for the subsequent evaluation of ecological environment and monitoring and analysis.In addition to the above results, this study mainly has the following deficiencies:(1) The influence of the hydro-fluctuation belt on the distribution of soil erosion has not been fully considered.(2) Based on the measured data, the remote sensing inversion model of suspended sediment concentration can only obtain the suspended sediment concentration of the surface layer of water.(3) Due to the limitation of field survey conditions, the water spectrum of the study area was not measured, and the understanding of the physical mechanism of remote sensing inversion of suspended sediment concentration was insufficient. 
Pages140
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24777
Collection中国科学院水利部成都山地灾害与环境研究所
Affiliation中国科学院成都山地灾害与环境研究所
First Author Affilication中国科学院水利部成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
张茜彧. 溪洛渡库区生态环境变化遥感监测与评价研究[D]. 北京. 中国科学院大学,2018.
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